A loom is used to produce a fabric obtained by mixing plural warp yarns and fill yarns. The loom is largely classified into a shuttle loom and a shuttle-less loom.
In the weaving using the shuttle loom, plural warp yarns aligned in one direction through a mail of a heddle are guided so that a part of the warp yarns are moved up and a part of the warp yarns are moved down so as to form a rhombic opening between the warp yarns in a manner such that the heddle is moved up and down based on the weave texture. While the opening is formed, a shuttle for accommodating and holding a fill yarn bobbin is beaten into a shuttle path formed inside the opening. The fill yarn is drawn out from the bobbin accommodated inside the shuttle by the beating. When the beating ends, a dent which is disposed between the heddle and the cloth fell position swings toward the cloth fell position, so that the fill yarn is pressed into the cloth fell position. The weaving is performed by repeating these operations.
The weaving using the shuttle-less loom is different from the weaving using the shuttle loom in that the above-described shuttle is not used and the fill yarn directly passes through the opening formed by the warp yarns. The shuttle-less loom may be classified into plural types in accordance with a difference in the method of inserting the fill yarn into the opening. As one of representative looms, there is known a water jetting loom which loads a fill yarn on a water jetting stream so that the fill yarn is inserted into a shuttle opening. As the other looms, there is known a needle loom in which a fill yarn is gripped by a front end of a needle moving in a reciprocating manner inside an opening of warp yarns, the needle is moved in a reciprocating manner inside the same opening, and loops of the adjacent folded-back portions are sequentially connected and matched by a knitting needle so as to obtain a fabric or a rapier loom in which a rapier formed as a stab member is disposed at the left and right sides of the loom and a front end of a fill yarn is moved in a reciprocating manner to the inside or the outside of the opening by the entire weaving width or a half of the weaving width while the front end thereof is gripped or released by a carrier head of each front end of the left and right rapiers so that the fill yarn is directly inserted into the opening.
These conventional looms respectively have good and bad points.
For example, in the shuttle loom, the fill yarn is reliably inserted, but the amount of the fill yarn accommodated and held by the shuttle is limited. Further, since the fill yarn is inserted while the shuttle flies along the shuttle path through the beating of the shuttle, the weight of the entire shuttle including the fill yarn is also limited. Accordingly, the mechanical beating sound generated by the fill yarn inserting operation is large, and hence a noticeable noise is generated. In one shuttle-less loom, noise may be solved by reducing the mechanical sound. However, for example, in the general shuttle-less loom, the operation of controlling the fill yarn length and the fill yarn end process at the ear portion of the edge of the weaving width is complex. Further, in the water jetting loom, various techniques of ensuring the straight traveling of the water are needed, and the adverse influence caused by the use of the water needs to be handled in various respects. Further, in the gripping rapier loom, mistakes may be caused during the operation of delivering the front end of the fill yarn by the carrier head or cutting the yarn end.
For example, when producing a carbon fiber under such circumstances, various precursor fibers are bound as one fiber bundle, and plural fiber bundles are disposed in parallel as a sheet. The fiber bundles are introduced into a flame-resistant furnace in the atmosphere of oxidization so as to be subjected to a flame-resistant process at 200 to 300° C. and are subsequently carbonized in a sintering furnace at 500 to 1500° C. in the atmosphere of nitrogen. The sintering speed at this time is generally 5 to 10 m/minute. Meanwhile, there is a recent demand for the improvement of the productivity, and hence the sintering speed and the total fiber fineness of the fiber bundle tend to increase. As the precursor fiber, acrylonitrile-based fibers are used in many cases.
As described above, when the flame-resistant process is continuously performed on various thick fiber bundles while running and being disposed in parallel in a sheet state, the maximal thickness of one fiber bundle increases, so that oxygen does not widely spread into the fiber bundles and the yarn is easily damaged due to the accumulation of heat. In order to prevent this problem, the flame-resistant process needs to be performed for a long period of time by decreasing the temperature of the flame-resistant process. However, since there is a difference in progress of the flame-resistant process between the inside and the surface of the fiber bundle, a nap may be raised or a yarn is damaged in the subsequent carbonizing process. For this reason, it is difficult to obtain the high-quality carbon fiber.
In order to continuously produce the carbon fiber, a method is proposed in which a carbonizable fiber filament bundle having thick fiber fineness is flattened as described above, the fiber filament bundle is disposed in parallel so as to become a band-like material, and the band-like material is sintered at a high temperature. However, in a case where a material obtained just by disposing the fiber bundle in a band shape is sintered at a high temperature, the nap of the single fiber forming the band-like material in the flame-resistant process or the ends of the damaged yarns is particularly wound on a roller inside a furnace or is tangled with the adjacent fiber bundles inside the furnace, and hence the more naps occur or the more yarns are damaged. As a result, the continuous sintering process needs to be stopped without any choice.
In order to solve these problems, for example, JP 10-266024 A (Patent Literature 1) proposes a method in which the precursor fiber bundle is guided inside the flame-resistant furnace in a zigzag shape by a rectangular guide groove to multi-stage guide rolls provided at the inlet and the outlet of the flame-resistant furnace and the precursor fiber bundle guided inside the flame-resistant furnace is maintained, through the guide groove, in a state where the cross-sectional shape thereof becomes a substantially rectangular shape in which the oblateness defined by the transverse width and the yarn thickness of the fiber bundle is 10 to 50.
Further, in order to exclude the above-described problems, for example, JP 51-75150 A (Patent Literature 2), JP 61-63718 A (Patent Literature 3), and U.S. Pat. No. 4,173,990 (Patent Literature 4) proposes a method in which various precursor fiber bundles formed in a sheet shape are formed by warp yarns and are mixed with fill yarns so as to form a fabric by weaving. Here, in Patent Literatures 2 and 3, one fill yarn is folded back toward the end of the entire weaving width so as to be mixed with the warp yarn. However, in Patent Literature 4, the rapier formed as a pair of double tubes is disposed at the left and right side of the loom in the width direction, the fill yarns are respectively inserted through the inner tubes of the left and right rapiers, the front ends of the respective fill yarns are gripped and conveyed by using the air pressure transferred to the outer tube of the rapier, and the respective fill yarns are folded back to the center portion inside the opening formed by the warp yarns. Here, the weaving is performed by alternately repeating the operations of inserting and separating the left and right rapiers into and from the opening with a predetermined time interval therebetween.
Meanwhile, in Patent Literatures 2 and 3, for example the flame-resistant process is performed on the precursor fiber bundles as the adjacent warp yarns to be introduced into the flame-resistant furnace for the process thereof while the fill yarns are inserted thereinto and the precursor fiber bundles are separated by the fill yarns so as to prevent the contacting or the lapping thereof. Then, in Patent Literatures 2 and 3, the fill yarn is automatically removed from the fabric after the flame-resistant process, and various fiber bundles subjected to the flame-resistant process are introduced into the carbonizing furnace while being simply aligned.